It theoretically could.
What reports have been failing to say is that the fiter will be mandatory for Optus customers. It looks like it'll be mandatory for Telstra customers too. It's likely to be the same for iPrimus customers as well.However, three of Australia's largest internet service providers have agreed to voluntarily block online child pornography material ahead of the Federal Government's planned internet filter. This includes Telstra, Optus and Primus.
So if anyone here is with any of those three ISPs I recommend switching to another ISP ASAP. And let Telstra/Optus/iPrimus know why you're switching to a different ISP.